QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

4km ENE of El Sobrante, CA

· 10 km deep · released about 400 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 28 kmSolano County 42 kmMarin County 44 kmAlameda County 48 kmNapa County 58 kmSan Mateo County 64 kmSan Francisco County 74 kmYolo County 83 kmSonoma County 84 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 2.8 (md)
Depth
10 km below the surface
Felt
328 reports · strongest reported intensity III
Nearest
Contra Costa County, 28 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 237 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 328 people have reported feeling it to USGS.

How big was it?

This earthquake released about 400 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 38,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 27,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.4× the energy of this one
  4. This earthquake M 2.8 about 400 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

Where

Epicentre 37.9862, -122.2555. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 28 km (17 mi) WNW of here earthquakes near Contra Costa County
Solano County, CA 42 km (26 mi) SW of here earthquakes near Solano County
Marin County, CA 44 km (27 mi) E of here earthquakes near Marin County
Alameda County, CA 48 km (30 mi) NW of here earthquakes near Alameda County
Napa County, CA 58 km (36 mi) S of here earthquakes near Napa County
San Mateo County, CA 64 km (40 mi) N of here earthquakes near San Mateo County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

55 earthquakes have been recorded within 50 km since this one.

  1. 1.5 4km WSW of Colma, CA
  2. 1.7 5km WSW of Pacheco, CA
  3. 1.5 2km NE of Union City, CA
  4. 2.0 5km W of Yountville, CA
  5. 2.6 2km SW of Colma, CA
  6. 1.5 2km S of Alamo, CA
  7. 2.3 4km NE of Fairview, CA
  8. 1.6 2km NE of San Ramon, CA
  9. 1.9 1km NW of Danville, CA
  10. 1.7 1km WNW of Danville, CA
  11. 2.0 1km N of Pacifica, CA
  12. 1.6 6km E of Vallejo, CA
  13. 1.9 6km E of Vallejo, CA
  14. 1.6 3km SE of Concord, CA
  15. 1.6 7km WSW of Lagunitas-Forest Knolls, CA

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.5 on 2019-10-15 — it released about 370 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.